Inkjet printer with substrate height position control

ABSTRACT

An inkjet printer is described. The inkjet printer has a substrate holder assembly that includes a base member having a long axis in a first direction and a short axis in a second direction perpendicular to the first direction; a contact member coupled to the base member, the contact member having a long axis in the first direction and a short axis in the second direction; a holder carriage coupled to the base member; a linear extender coupled between the base member and the contact member and extending in a third direction intersecting with the first direction and the second direction from the base member toward the contact member; and a flex member coupled to the base member, extending in the second direction between the linear extender and the contact member, and having a flex direction in a direction perpendicular to the first direction and the second direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/305,891, filed Jul. 16, 2021, which is a continuation of U.S.application Ser. No. 16/702,380, filed Dec. 3, 2019, issued as U.S. Pat.No. 11,097,560 on Aug. 24, 2021, which claims the benefit from U.S.Provisional Patent Application Ser. No. 62/775,487 filed Dec. 5, 2018,which are incorporated herein by reference.

FIELD

Embodiments of the present invention generally relate to inkjetprinters. Specifically, methods and apparatus for monitoring and controlof substrate position and orientation are described.

BACKGROUND

Inkjet printing is common, both in office and home printers and inindustrial scale printers used for fabricating displays, printing largescale written materials, adding material to manufactured articles suchas PCB's, and constructing biological articles such as tissues. Mostcommercial and industrial inkjet printers, and some consumer printers,use dispensers to apply print material to a substrate. The dispenserejects a controlled quantity of print material toward a substrate at acontrolled time and rate so that the print material arrives at thesubstrate in a target location and makes a mark having a desired sizeand shape.

In some cases, the precision of locating print material on the substrateis extreme. Micro-scale deviations in timing, quantity, or rate of printmaterial ejection can cause printing faults. Similarly, imprecision inpositioning the substrate to receive print material can cause the printmaterial to arrive at the substrate off target. For example, ifsubstrate distance from print ejectors is off target, the print materialtraverses a distance that is not expected, so the print material arrivesat the substrate early or late. There is a need for substrate heightcontrol in high precision inkjet printing applications.

SUMMARY

Embodiments described herein provide a substrate holder assembly,comprising a base member having a long axis in a first direction and ashort axis in a second direction perpendicular to the first direction; acontact member coupled to the base member, the contact member having along axis in the first direction and a short axis in the seconddirection; a holder carriage coupled to the base member; a linearextender coupled between the base member and the contact member andextending in a third direction intersecting with the first direction andthe second direction from the base member toward the contact member; anda flex member coupled to the base member, extending in the seconddirection between the linear extender and the contact member, and havinga flex direction in a direction perpendicular to the first direction andthe second direction.

Other embodiments described herein provide an inkjet printer, comprisinga substrate support; a dispensing assembly attached to the substratesupport; and a holder assembly attached to the substrate support, theholder assembly comprising a holder carriage operatively coupled to aslide attached to the substrate support; a base member coupled to theholder carriage and having a long axis in a first direction along a sideof the substrate support; a contact member coupled to the base memberand having a long axis in the first direction, the contact member havinga manipulator at an edge of the contact member adjacent to the substratesupport; a first linear extender coupled to the base member andextending from the base member toward the contact member at a locationadjacent to the edge of the contact member having the manipulator; afirst flex assembly coupled to the base member and extending toward themanipulator; a second linear extender coupled to the base member andextending from the base member toward the contact member at a locationadjacent to the edge of the contact member having the manipulator; and asecond flex assembly coupled to the base member and extending toward themanipulator.

Other embodiments described herein provide a substrate holder assembly,comprising a holder carriage; a base member coupled to the holdercarriage and having a long axis in a first direction; a contact membercoupled to the base member such that the base member is between theholder carriage and the contact member, the contact member having a longaxis in the first direction, the contact member having a manipulatorextending along a long edge of the contact member; a first linearextender coupled to the base member and extending through the basemember to the contact member at a location adjacent to the edge of thecontact member having the manipulator; a first flex assembly coupled tothe base member and extending toward the manipulator; a second linearextender coupled to the base member and extending through the basemember to the contact member at a location adjacent to the edge of thecontact member having the manipulator; and a second flex assemblycoupled to the base member and extending toward the manipulator.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlyexemplary embodiments and are therefore not to be considered limiting ofits scope, may admit to other equally effective embodiments.

FIG. 1 is a top isometric view of an inkjet printer according to oneembodiment.

FIG. 2 is a plan view of a substrate support according to oneembodiment.

FIG. 3 is a side view of a print assembly according to one embodiment.

FIG. 4 is a top isometric view of a holder assembly for the inkjetprinter of FIG. 1 , according to one embodiment.

FIG. 5 is a cross-sectional view of a portion of the holder assembly ofFIG. 4 .

FIG. 6 is a detail view of a portion of the holder assembly of FIG. 4 .

FIG. 7A is a plan view of the holder assembly of FIG. 4 .

FIG. 7B is a cross-sectional view of a portion of the holder assembly ofFIG. 4 .

FIG. 8A is an activity diagram illustrating substrate edge positioningaccording to one embodiment.

FIG. 8B is an activity diagram illustrating substrate edge positioningaccording to another embodiment.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

DETAILED DESCRIPTION

An inkjet printer is described herein with height control features toensure precision in placement of print material on a substrate. FIG. 1is a top isometric view of an inkjet printer 100 according to oneembodiment. The inkjet printer has a substrate support 102, a printassembly 104, and a holder assembly 106 for manipulating a substrate forprinting. The printer 100 is founded upon a base 108, which is typicallya massive object to minimize vibratory transmissions to the operativeparts of the printer 100. In one example, the base 108 is a graniteblock. The substrate support 102 is located upon the base 108, andcomprises a support surface 110 along with means for making the supportsurface 110 substantially frictionless. Here, the support surface 110 isan air table that provides a gas cushion on which the substrate floats.The support surface 110 features a plurality of holes 112 that allowjets of gas to exit, thus providing an upward force to maintain asubstrate at a desired elevation above the support surface 110. Some ofthe holes may also allow controlled withdrawal of gas from the gascushion floating the substrate support to provide precise local controlof substrate elevation.

The print assembly 104 comprises a dispenser assembly 114 disposed on aprint support 116. The print support 116 is disposed in relation to thesubstrate support 102 to provide access for the dispenser assembly 114to position constructively in relation to a substrate on the substratesupport 102 so that print material can be precisely applied to thesubstrate. Here, the print support 116 includes a rail or beam 117 thattraverses the substrate support 102, allowing the dispenser assembly 114to traverse the substrate support 102 and deposit print material at anylocation on the substrate from one side of the print support 116 to theopposite side thereof. In this embodiment, the print support 116 isattached to the base 108 and extends from the base 108 to provide stablesupport for the dispenser assembly 114. Two stands 120 extend from thebase 108, on opposite sides of the substrate support 102, to the rail117, which extends across the substrate support 102. The stands 120 andthe rail 117 can both be made of the same material as the base 108. Inthis case, the stands 120, the rail 117, and the base 108 are integrallyformed from one piece of granite.

The dispenser assembly 114 typically includes one or more dispensers 119along with a print assembly controller 118 that includes electronics andsensors for controlling the functional parameters of the dispensers 119such as location of the dispensers 119 along the print support 116,timing, duration, type of print material, and dispensing profile. Thedispensers 119 typically ride along the print support 116 by operationof a print carriage 122 that couples with the print support 116 totranslate the dispensers 119 along the rail 117 from one end of the railto the other opposite end. Power and signal conduits are not shown tosimplify the figures.

A substrate is positioned under the print assembly 104 by the holderassembly 106. The holder assembly 106 acquires secure contact with thesubstrate upon loading and moves the substrate along the substratesupport 102 to position the substrate with respect to the print assembly104 for dispensing print material onto the substrate in a precisefashion. The holder assembly 106, in this case, is located on one sideof the substrate support 102 and generally extends along the substratesupport 102 in a first direction to translate the substrate in the firstdirection during printing. The first direction is denoted in FIG. 1 byarrow 124. The dispensers 119 generally move in a second directionsubstantially perpendicular to the first direction, as determined by therail 117, which extends substantially in the second direction, denotedin FIG. 1 by arrow 126. The second direction 126 is sometimes referredto as the “x direction,” and the rail 117 as the “x beam.”

The holder assembly 106 is generally disposed on a holder assemblysupport 128, which in this case is a rail that extends in the firstdirection substantially the entire length of the substrate support 102along an edge 130 of the substrate support 102. In this embodiment, theholder assembly support 128 is attached to the base 108 to providestable support for the holder assembly 106. The holder assembly support128 may be made from the same material as the base 108. In this case,the holder assembly support 128, base 108, and print support 116 areintegrally formed from one piece of granite. Sometimes, the holderassembly support 128 is referred to as a “y beam”.

The holder assembly 106 comprises a holder carriage 132 that rides alongthe holder assembly support 128. A base member 134 is coupled to theholder carriage 132 and a contact member 136 is coupled to the basemember 134 with the base member 134 between the holder carriage 132 andthe contact member 136. The contact member 136 includes a manipulator138 located at an edge 140 of the contact member 136 nearest the edge130 of the substrate support 102. Here, a vacuum source (not shown) iscoupled to the holder assembly 106 to provide vacuum at a contactsurface 142 of the manipulator 138 to securely hold a substrate forprocessing on the substrate support 102. The holder assembly 106 movesalong the holder assembly support 128 during operation to position thesecurely held substrate at any location on the substrate support 102such that the print assembly 104, for example by operation of the printassembly controller 118, can position the dispensers 119 to provideaccess to a precise location on the substrate for dispensing printmaterial.

A system controller 129 receives signals from various sensors that maybe deployed throughout the printer 100 and sends signals to the systemsof the printer 100 to control printing. Here, the system controller 129is shown operationally coupled to the print assembly controller 118 andto a holder assembly controller 131, which controls operation of theholder assembly 106. Each of the substrate support 102, the printassembly 104, the holder assembly 106, and potentially other ancillarysystems such as environment control and materials management systems,may have sensors operatively coupled to the system controller 129 totransmit signals to the system controller 129 related to the status ofvarious components during a print operation. The system controller 129includes data and instructions to determine control signals to send tovarious controlled components of the printer 100.

When printing on a substrate, it is often desired to place microscopicdroplets of print material, for example print material droplets havingdiameter of 5-10 μm in an area of the substrate of dimension 10-15 μm.In this operation, the print material is typically dispensed while thesubstrate is moving to minimize print time. This extreme precision iscomplicated by tiny imperfections in the dimensions of the various partsof the print system, variation of those dimensions with temperature,imprecision in speed of translation of the substrate, the dispenserassembly, and the holder assembly 106, and imprecision in the distanceof the substrate from the dispensers 119. If distance of the dispensers119 to the substrate is not precisely known or controlled, dropletvelocity of print material from the dispensers 119 cannot be programmedfor the print material droplet to arrive at the target location when thesubstrate is in the proper position. The droplet arrives too early ortoo late and misses the target.

Apparatus and methods for controlling distance of the substrate from thedispensers 119, sometimes referred to as “fly height” when the substrateis floated on a gas cushion, are described herein. One or more sensorsis included in the substrate support 102 or the print assembly 104 tosense one or more distances of the substrate, for example from thesubstrate support 102 or some part of the print assembly 104. FIG. 2 isa plan view of a substrate support 200 according to one embodiment. Thesubstrate support 200 may be used as the substrate support 102 in theprinter 100 of FIG. 1 . The substrate support 200 includes a firstplurality of holes 202 formed in a support surface 201 of the substratesupport 200 for providing gas between the support surface 201 and asubstrate disposed thereon to establish a gas cushion for supporting thesubstrate at a target height above the support surface 201. Thesubstrate support 200 also includes a second plurality of holes 204formed in the support surface 201 for providing suction between thesupport surface 201 and the substrate disposed thereon. A gas source(not shown) comprising an inert gas is fluidly coupled to the firstplurality of holes 202 and a vacuum source (not shown) is fluidlycoupled to the second plurality of holes 204. The gas source and vacuumsource are operated to provide a gas cushion of a target thicknessand/or pressure between the substrate and the support surface 201. Here,the first plurality of holes 202 is uniformly spread across the supportsurface 201 substantially from end to end of, and entirely across, thesupport surface 201. The second plurality of holes 204 is interspersedwith the first plurality of holes 202 in a central area 205 of thesupport surface 201. The vacuum provided through the second plurality ofholes 204 works in conjunction with the gas cushion provided through thefirst plurality of holes 202 in the central area 205 to provide controlover the height of the substrate above the support surface 201 in thecentral area 205 where deposition of print material on the substratetakes place.

A plurality of distance sensors 206 is disposed in the support surface201 to sense a distance between the substrate and the support surface201. Because the substrate can be large, a plurality of sensors 206 canbe used to sense the distance at multiple parts of the substrate. Inother cases, a single sensor 206 can be used. Here, the sensors 206 areshown regularly spaced in the support surface 201. The sensors 206 canbe capacitive, inductive, optical, or acoustic, or a mixture thereof. Inone embodiment, only capacitive sensors are used. In another embodiment,capacitive and optical sensors are used. The optical sensors may beinterference based, diffractive, spectral, and/or triangulation-based.The distance sensors 206 can be operatively coupled to the systemcontroller 129 (FIG. 1 ) to send signals representing the senseddistance to the system controller 129. Each sensor 206 sends a signalrelated to the distance of the substrate from the sensor 206, along withan identity code. The system controller 129 receives the signal and theidentity code and stores the signal and the identity code. The systemcontroller 129 also converts the signal into a distance, and may convertthe identity code into a location of the support surface 201 based on apredetermined mapping of the sensors 206.

The type and density of the sensors 206 may vary across the supportsurface 201. For example, some areas of the support surface 201 may haveno sensors 206 if distance from the support surface 201 is not sensed inthat area. Some areas may have a low density of sensors 206 if lowgranularity of distance measurement is sufficient in that area. Otherareas may have a high density of sensors 206 if high granularity ofmeasurement is desired in that area. In this case, the support surface201 has a high granularity of sensors 206 in the zone proximate to theprint assembly 104 where print material is dispensed to provide moreprecise control of substrate distance from the dispensers 119 (FIG. 1 ).

In another embodiment, one or more sensors may be attached to the printassembly. FIG. 3 is a side view of a print assembly 300 according to oneembodiment. The print assembly 300 may be used as the print assembly 104in the printer 100 of FIG. 1 . The print assembly 300 includes similarelements to the print assembly 104 of FIG. 1 , which will be labeledusing the same reference numerals. The print assembly includes one ormore sensors 302 for sensing a distance of the substrate. One sensor 302is shown here mounted on the print support 116. Another sensor 302 isshown here mounted on the print carriage 122. Another sensor 302 isshown mounted on one of the dispensers 119. Any or all of these sensors302 can be used to sense a relevant distance of the substrate. Ifmultiple sensors 302 are used, perhaps along with sensors 206 in thesupport surface 201 of the substrate support 200, multiple distancereadings can be compared by the system controller 129 and an estimate ofdistance having improved accuracy may result. The sensors 302 may beoptical or acoustic. Any of the optical sensors described above can beused for the sensors 302. The sensors 302 are shown here operativelycoupled to the print assembly controller 118 to send signalsrepresenting distance readings to the print assembly controller 118. Itshould be noted that the sensors 302 and other operative elements of theprint assembly 104 may be directly operatively connected to the systemcontrol 129 without using a print assembly controller.

Substrate height can be controlled by adjusting the gas cushionsupporting the substrate. If substrate height is adjusted up or down, aslight curvature may develop near the edge of the substrate contactingthe holder assembly if the holder assembly is not also adjusted. FIG. 4is an isometric view of a holder assembly 400 according to oneembodiment. The holder assembly 400 has the capability to adjust theedge of the substrate in a direction perpendicular to the supportsurface 201 of the substrate support 200 (or 102). The holder assembly400 can be used as the holder assembly 106 described above.

The holder assembly 400 has a carriage member 402, a base member 404coupled to the carriage member 402, and a contact member 406 coupled tothe base member 404 such that the base member 404 is between the contactmember 406 and the carriage member 402. The contact member 406 contactsthe substrate along an edge thereof using vacuum to make stable securecontact with the substrate. A vacuum source (not shown) is fluidlycoupled to the holder assembly 400 to provide vacuum force. The carriagemember 402 supports substantially frictionless motion of the holderassembly 400 along the holder assembly support 128.

The base member 404 has a long axis 405 that extends in the firstdirection 124 and is substantially the same as the dimension of thesupport surface 201 (FIG. 2 ) of the substrate support 102 in the firstdirection 124. The base member 404 has a short axis 407 in the seconddirection 126. The base member 404 may be plate-like, and may havevarious openings for fasteners, sensors, actuators, and the like. Thebase member 404 is fastened to the carriage member 402 to provide stablesupport for the contact member 406 as the carriage member 402 translatesalong the holder assembly support 128. In this embodiment, the basemember 404 extends beyond the ends of the carriage member 402 in thefirst direction 124 and the carriage member 402 is centrally locatedwith respect to the base member 404. Here, the base member 404 isrectangular in profile.

The contact member 406 is adjustably coupled to the base member 404. Thecontact member 406 includes a fulcrum 408, a manipulator stage 410, amanipulator 412 coupled to the manipulator stage, and a plurality oflanding members (discussed further below) for attaching sensors and/orpositioners to be described below. The contact member 406 has a longaxis 409 in the first direction 124 and a short axis 411 in the seconddirection 126, and is substantially similar in length to the base member404. The contact member 406 also has a rectangular profile, like thebase member, since the fulcrum 408, the manipulator stage 410, and themanipulator 412 all extend substantially the length of the base member404. The manipulator stage 412 is located at a support edge 416 of thecontact member 406 adjacent to the substrate support 102 and is adjacentto a proximate edge 418 of the base member 404. The fulcrum 408 islocated at an adjustment edge 420 of the contact member 406 oppositefrom the support edge 416, and is adjacent to a corresponding oppositeedge 422 of the base member 404.

FIG. 5 is a cross-sectional view of the holder assembly 400 of FIG. 4 .A linear extender 502 is coupled to the base member 404 and extends fromthe base member 404 toward the contact member 406. The linear extender502 is located at the support edge 416 of the contact member 406 andextends toward the contact member 406 in a third direction 504perpendicular to the first and second directions. The linear extender502 may also extend somewhat in either or both of the first and seconddirections 124 and 126. The linear extender 502 may be any precisionpositioner capable of positioning an object to an accuracy of less than10 μm, such as a piezoelectric positioner. In the piezoelectricembodiment, a sample of a piezoelectric material is oriented to changelength in the third direction when voltage is applied, and the degree oflength change is directly and precisely related to the applied voltage.

A bearing member 506 is disposed between the linear extender 502 and thecontact member 406. The bearing member 506 is located adjacent to thebase member 404 at the support edge 416 of the contact member 406. Thelinear extender 502 applies a positioning force to the bearing member506, which in turn transmits the positioning force to the contact member406. The bearing member 506 extends in the first direction 124 and has alength substantially the same as the length, in the first direction 124,of the contact member 406. Thus, the bearing member 506 runs along thecontact member 406 substantially along the entire length of the contactmember 406 in the first direction 124. Here, the bearing member 506 ishollow to reduce weight, and the bearing member 506 has a dimension inthe second direction 126 larger than the dimension, in the seconddirection 126, of the manipulator stage 410 of the contact member 406.

A landing member 508 is disposed between the bearing member 506 and themanipulator stage 410. The landing member 508 mediates the positioningforce of the linear extender 502 on the contact member 406. The landingmember 508 may be made of a sturdy, resilient material to absorb anyimpulses or shocks that might be transmitted between the contact member406 and the bearing member 506. In other cases, the landing member 508may be an air bearing. A plurality of landing members 508 are provideddistributed along the length of the bearing member 506 and themanipulator stage 410 to provide stable consistent positioning supportalong the length of the manipulator stage 410.

The linear extender 502 changes length in the third direction 504 whenactuated. When the linear extender 502 extends, the bearing member 506is thrust toward the contact member 406 in the third direction 504 toshift the position of the support edge 416 of the contact member 406 inthe third direction 504. When a substrate is disposed on the manipulator412, the substrate contacts the manipulator 412 at a contact surface510. Vacuum is applied to the contact surface 510 through a vacuummanifold 512, which is a conduit running through the manipulator 412along a length thereof in the first direction 124. The pressuredifferential caused by the vacuum forces the substrate against thecontact surface 510 such that the substrate moves with the manipulator412, the manipulator stage 410, and the contact member 406. At thesupport edge 416, by operation of the linear extender 502, themanipulator 412 is moved in the third direction 504 such that a heightof the substrate above the substrate support 102 near the holderassembly 400 is modified.

Referring again to FIG. 4 , the contact member 406 includes a pluralityof braces 424 that couple the manipulator stage 410 to the fulcrum 408.Here, there are four braces 424, two at the opposite ends of the fulcrum408 and two near the center of the contact member 406 on either sidethereof. The fulcrum 408, in this case, has a dimension in the firstdirection 124 that is less than a dimension of the manipulator stage 410in the first direction 124. The braces 424 serve to couple the fulcrum408 securely to the manipulator stage 410 such that the two move as aunit and the contact member 406 has structural integrity. The braces 424are here oriented along the second direction 126, and are bar-likemembers that extend from the fulcrum 408 to the manipulator stage 410.Each brace 424 is disposed between the fulcrum 408 and the base member404 and between the manipulator stage 410 and the bearing member 506,and each brace 424 is in direct contact with both the fulcrum 408 andthe manipulator stage 410. Each brace 424 also forms a right angle withthe fulcrum 408 and with the manipulator stage 410.

One brace 424 is visible in FIG. 5 . A second landing member 508 isdisposed between the base member 404 and the fulcrum 408, shown herebehind the brace 424. The second landing member 508 supports the fulcrum408 at the adjustment edge 420 of the contact member 406. As the linearextender 502 extends, thus moving the bearing member 506, the landingmember 508, the manipulator stage 410, and the manipulator 412 in thethird direction 504, the brace 424 couples the motion of the foregoingmembers at the support edge 416 to the fulcrum 408 at the adjustmentedge 420. Because the positioning force of the linear extender 502 isnot directed through a centroidal axis of the contact member 406, thecontact member 406 rotates such that the fulcrum 408 does not move inthe third direction 504. The contact member 406 thus forms an angle θwith respect to the base member 404. The angle θ is typically, at most afew microradians in extent, for example from zero to 100 microradians.The second landing member 408 may also be an air bearing.

The base member 404 includes a support block 428 that supports a firstflex member 430 and a second flex member 432, forming a pair of flexmembers. The support block 428 has a first side 434 that contacts thebase member 404. Here, the second landing member 408 contacts the basemember 404 on a first side 514 thereof and the support block 428contacts the base member 404 on a second side 516 thereof, opposite fromthe first side 514. The base member 404 is thus disposed between thesecond landing member 408 and the support block 428. The first side 514of the base member 404 has a shelf 518 located between the secondlanding member 508 and the proximate edge 418 o the base member 408. Atthe shelf 518, the base member 404 changes thickness from a firstthickness between the support block 428 and the second landing member508 to a second thickness, the second thickness being less than thefirst thickness. Thus, as the base member 404 extends from a locationadjacent to the fulcrum 408 to a location toward the manipulator stage410, the base member 404 declines in thickness at the shelf 518.

The first flex member 430 is attached to the first side 514 of the basemember 404 opposite from the location where the support block 428 isattached to the second side 516 of the base member 404, between thefulcrum 408 and the base member 408. The first flex member 430 extendsin the second direction 126 toward the manipulator stage 410, beyond theshelf 518 and the proximate edge 418 of the base member. At the shelf518, a gap 520 is formed between the first flex member 430 and the basemember 404 that allows the first flex member 430 freedom to flex in thethird direction 504. The first flex member 430 thus has a flex directionin the third direction 504. The first flex member 430 extends to aposition between the bearing member 506 and the manipulator stage 410.The first flex member 430 is fixed to the base member 404 by a firstcapture plate 522, being disposed between the base member 404 and thefirst capture plate 522 and fastened by convenient fasteners, such asbolts. The first flex member 430 is fixed to the bearing member 506, ata first side 528 thereof, by a second capture plate 524, the first flexmember 430 being disposed between the second capture plate 524 and thebearing member 506. In this way, as the bearing member 506 is moved inthe third direction 504 by the linear extender 502, the first flexmember 430 flexes in the third direction 504 to provide a restorativeforce opposing the positioning force of the linear extender 502. As canbe seen in FIG. 5 , the landing member 508 is in supporting relationshipwith the first side 528 of the bearing member 506 and with themanipulator stage 410.

The second flex member 432 extends from a second side 526 of the supportblock 428, opposite from the first side 434, and is fixed to the secondside 526 of the support block 428 by a third capture plate 530, which isfastened to the support block 428 by convenient fasteners, such asbolts. Here, the first and second members 430 and 432 are the samelength. The second flex member 432 extends in the second direction 126toward the bearing member 506. Here, the bearing member 506 is a hollowtube with a square profile. The second flex member 432 is attached to asecond side 532 of the bearing member 506 opposite from the first side528. The second flex member 432 is fixed to the second side 532 of thebearing member 506 by a fourth capture plate 534, the second flex member432 being disposed between the fourth capture plate 534 and the secondside 532 of the bearing member 506. The fourth capture plate 534 isfastened to the second side 532 of the bearing member 506 by convenientfasteners, such as bolts.

The linear extender 502 is here disposed through the second side 532 ofthe bearing member 506 to contact the first side 528 of the bearingmember 506 at an interior surface 536 of the first side 528. A pressuremember 538 at a force end 540 of the linear extender 502 contacts theinterior surface 536 of the first side 528. The pressure member 538applies the positioning force to the interior surface 536 of the firstside 528 of the bearing member 506. The bearing member 506 contacts thefirst flex member 432 at an exterior surface 542 of the first side 528,transmitting the positioning force through the first flex member 432 tothe manipulator stage 410 of the contact member 406, and thus to themanipulator 412. The manipulator 412 moves in response to thepositioning force applied by the linear extender 502 to a preciselocation determined by the actuation control, for example voltage in thecase of a piezoelectric element, applied to the linear extender 502.When in contact with a substrate disposed on the substrate support 102,the linear extender 502 accomplishes precision positioning of the edgeof the substrate in the third direction 504. Thus, the linear extender502 precisely affects the elevation of the edge region of the substrateabove the substrate support 102, preventing contact between the edgeregion and the substrate support surface 201 in the event the elevationof the substrate changes in other regions. In this case, the linearextender 502 has a movement range of about 100 μm, but the movementrange of the linear extender 502 can be selected based on the specificarchitecture and scale of the system. The first and second flex members430 and 432, and in this orientation gravity, provide restorative forceopposing the positioning force of the linear extender 502 on the bearingmember 506 such that when actuation of the linear extender 502 isdiscontinued or lessened, the restorative force of the flex members 430and 432 moves the bearing member 506 in a direction opposite to thedirection of the positioning force, reducing the elevation of thesubstrate at the edge of the substrate support 102.

The linear extender 502 is supported by an extension 546 of the basemember 404 that extends from the second side 516 of the base member 404in the second direction 126 toward the bearing member 506. A stirrup 544extends from the extension 546 in alignment with the linear extender502, which is positioned in the stirrup 544. Here, the linear extender502 is a cylindrical body with an axis that extends in the thirddirection 504, and may also extend somewhat in the first and seconddirections 124 and 126. The linear extender 502 is disposed with asupport end 548 thereof, opposite from the force end 540, in the stirrup544. The linear extender 502 extends through the fourth capture plate534, the second flex member 432, and the second side 532 of the bearingmember 506 to the interior of the bearing member 506, culminating in theforce end 540 and the pressure member 538 disposed against the interiorsurface 536 of the first side 528 of the bearing member 506. Whenactuated, the linear extender 502 thus produces a separating forcebetween the stirrup 544 and the bearing member 506 to move the bearingmember 506 in the third direction 504 with respect to the stirrup 544and the base member 404 to which the stirrup 544 is attached. Asmentioned above, when actuation of the linear extender 502 isdiscontinued or lessened, the flex members 430 and 432 reverse themotion in the third direction 504.

Referring again to FIG. 4 , the holder assembly 400 has two linearextenders (not visible in FIG. 4 ) positioned to supply stablepositioning forces to the contact member 406, one on either side of acenter line of the contact member 406. The position of the linearextenders can be seen by reference to the two support blocks 428, thefirst flex members 430, and the capture plates 522, 524, and 530. Thebearing member 506 is also visible. The two linear extenders allow thetwo ends or sides of the contact member 406 to be differentiallyactuated in the third direction 504, if necessary, providing acapability to rotatably position a substrate about an axis in the seconddirection 126, sometimes referred to as a θ-x positioning capability.Each linear extender has a flex member pair, as shown in FIG. 5referencing the first flex member 430 and the second flex member 432.Each flex member pair, and each linear extender, is coupled to theapparatus as shown in FIG. 5 .

The linear extenders 502 described above cooperate with the flex members430 and 432 to position the manipulator 412 in the third direction 504,so the linear extenders 502 are sometimes referred to as z-positioners.The holder assembly 402 also has linear positioners 436. There are twolinear positioners 436, a first linear positioner 436 and a secondlinear positioner 436, in the version of FIG. 4 located near theopposite ends of the holder assembly 402. Each linear positioner 436 isdisposed beside a respective encoder 438 and positions the contactmember 406 in the second direction 126 by applying a positioning forceto the contact member 406 in the second direction 126. Each linearpositioner 436 includes an extension member 442 disposed in acontainment 444 and against a wall 446. One of the linear positioners436 and the encoders 438 are visible in FIG. 5 . The extension member442 has a first end that abuts the wall 446 and a second end that isdisposed in the containment 444. The encoder 438 includes a pair ofposts 552 on which is supported a scale 550. The posts 552 are attachedto a brace 424 of the contact member 406. A side wall 556 of thecontainment 444 is visible between the posts 552 and through a gapbetween the brace 424 and the first flex member 430. The containment 444is attached to the base member 404. The wall 446 is attached to thefulcrum 408 of the contact member 406. A read head 554 is attached tothe containment 444 and projects into alignment with the scale 550.

FIG. 6 is a detail view of one of the linear positioners 436 andencoders 438 of the holder assembly 400 of FIG. 4 . This view looks fromthe position of the fulcrum 408 toward the manipulator stage 410. Theextension member 442 is visible disposed inside the containment 444 andextending out of the plane of the figure. The read head 554 includes asupport 602 attached to the containment 444 and a reader 604 attached tothe support 602. The reader 604 is aligned with a metric 608 that liesatop the scale 550 of the encoder 438. The posts 552 support the scale550 from one side such that the scale 550 extends from the posts 552toward the containment 444. The reader 604 can thus be positionedbetween the scale 550 and the brace 424 in alignment with the metric608. The metric 608 is applied at an external surface 610 of the scale550 facing the reader 604.

The encoder 438 produces a signal representing a position of the reader604 with respect to the metric 608. The metric 608 is attached to thecontact member 406 by operation of the posts 552 attached to the brace424. The reader 604 is attached to the base member 404 by operation ofthe support 602 and the containment 444. If the contact member 406 movesin the third direction 126 relative to the base member 404, the reader602 registers a shift in position of the metric 608. To compensate forsuch a shift, the extension member 442 can be energized to apply apositioning force in the second direction 126 to the wall 446 (FIG. 5 ),and thus to the fulcrum 408 of the contact member 406. The extensionmember 442 is a two-way positioner, meaning that energy can be appliedthat extends or retracts the extension member 442. The extension member442 may be pneumatic, electromagnetic, electromechanical, or any two-wayactuatable extension member.

Referring again to FIG. 5 , when the linear extender 502 (one of two inthe embodiment of FIG. 4 ) extends in the third direction 504, rotationof the contact member 406 changes the angle θ of the contact member 406with respect to the base member 404. In addition to movement of themanipulator 412 in the third direction 504, this results in movement ofthe manipulator 412 in the second direction 126. The encoder 438registers this movement in the second direction 126 and sends a signalindicating position of the contact member 406 with respect to the basemember 404 to the holder assembly controller 131 (FIG. 1 ), or to thesystem controller 129 in the absence of a separate holder assemblycontroller 131. In response, if the registered movement is not withintolerance, the holder assembly controller 131 or the system controller129 may send a signal energizing the linear positioner 438 to adjust theposition of the contact member 406 in the second direction 126. As shownin FIG. 4 and discussed above, there are two linear positioners 438 inthe holder assembly 400. The two linear positioners 438 can be energizedtogether to adjust the position of the entire contact member 406 in thesecond direction 126 to compensate for any mispositioning in the seconddirection 126 due to rotation of the contact member 406 or due to anyother misalignments in the inkjet printer 100.

Referring again to FIG. 4 , the contact member 406 is coupled to thebase member 404 by a pivot 443 located near a center of both the contactmember 406 and the base member 404. The pivot 443 is coupled to the basemember 404 and extends through the contact member 406 between the twobraces 424 near the center of the contact member 406. A flex plate 450is disposed around the pivot 443 and extends to the braces 424 on eitherside of the pivot. The flex plate 450 is fixed to the two braces 424 byrespective capture plates 452, which are fastened to the braces 424 byconvenient fasteners, such as bolts.

FIG. 7A is a top view of the contact member 406 of FIG. 4 . A substrate702 is shown held on the manipulator 412. The components surrounding thetwo second linear positioners 438 are shown for reference. The pivot 443includes a pivot post 704 extending through the contact member 406 nearthe center thereof. The pivot post 704 extends through the flex plate450. The flex plate 450 allows the contact member 406 to move in thethird direction 504 according to positioning forces applied by thelinear extenders 502.

FIG. 7B is a cross-sectional view of a portion of the contact member 406of FIG. 4 . The pivot post 704 has a first end 720 and a second end 722.The first end 720 extends through the flex plate 450. The second end 722has a flange 724 that couples to a slide member 726.

The slide member 726 has a first surface 728, a second surface 730, anda hole 732 through the slide member 726 from the first surface 728 tothe second surface 730. The pivot post 704 extends through the hole 732in the slide member 726. The slide member 726 has a third surface 734connecting the first surface 728 with the second surface 730. The slidemember 726 also has a fourth surface 736, opposite the third surface734, and also connecting the first surface 728 with the second surface730.

A first groove 738 is formed in the third surface 734. A second groove740 is formed in the fourth surface 736. A first guide member 742extends from the base member 404 and engages with the first groove 738.A second guide member 744 extends from the base member 404 and engageswith the second groove 740. The slide member 726 slides along the guidemembers 742 and 744 to allow the slide member 726 to move in the seconddirection 126 (FIG. 7A).

The pivot post 704 is secured to the slide member 726, in this case, bya recess 746 formed in the second surface 730 of the slide member 726around the hole 732. The flange 724 engages with the recess 746, and iscaptured in the recess 746 between the slide member 726 and the basemember 404. The pivot post 704 extends through the flex plate 450, andis attached to the flex plate 450 by a center capture plate 710. Thecenter capture plate 710 and the flex plate 450 both have openings thatallow rotational movement of the center capture plate 710 and the flexplate 450 about the pivot post 704. In this way, the contact member 406can rotate about the pivot post 704. Motion of the slide member 726allows the contact member 406 to move in the second direction 126. Inanother embodiment, the pivot post 704 can be attached to the slidemember 726. In the embodiment shown in FIG. 7B, the second end 730 ofthe pivot post 704 can rotate within the recess 746 with respect to thebase member 404, for an extra degree of rotational freedom between thebase member 404 and the contact member 406.

In this way, the linear extenders 502 can be actuated according tosignals received from the system controller 129 or the holder assemblycontroller 131 to position the edge of the substrate 702 at a targetelevation above the support surface 201 of the substrate support 200 or102. The flex plate 450 flexes as the contact member 406 moves in thethird direction 506, thus providing an additional restorative forceopposing the action of the linear extenders 502. Additionally, thelinear positioners 438 can be actuated according to signals receivedfrom the system controller 129 or the holder assembly controller 131 tocompensate for displacement in the second direction 126 caused bymovement of the manipulator 412 in the third direction 504 and attendantrotation of the contact member 406. The slide member 726 allows thecontact member 406 to move in the second direction 126 to respond topositioning by the linear positioners 438. Finally, the linearpositioners 438 can be differentially actuated to compensate for anymisalignment of the substrate 702 or imperfection in positioning of theholder assembly 400 or 106 on the holder assembly support 128. The pivotpost 704 allows the contact member 406 to rotate about the pivot post704 according to the differential positioning applied by the linearpositioners 438. The system described herein achieves precisionpositioning of the substrate 702 for printing operations.

As noted above, the holder assemblies described herein have thecapability to adjust the position of the edge of the substrate in thethird direction, and thus to adjust a distance between the substrate andthe substrate support at the edge region of the substrate. Thiscapability can be useful in the event the overall positioning of thesubstrate in the third direction changes. In such cases, the position ofthe edge region of the substrate can be changed to adapt. FIG. 8A is anactivity diagram illustrating substrate edge positioning usingembodiments described herein. A substrate 826 is positioned over asubstrate support 802 for processing. Print material is to be ejectedfrom a dispenser 828 onto the substrate 802, which is supported abovethe substrate support 802 by a gas cushion. A holder assembly 822, whichmay be any of the holder assemblies described herein, is positionedadjacent to the substrate support 802. The holder assembly has a contactsurface 824, for example the contact surface 510 of FIG. 5 . Thesubstrate 826 is retained against the contact surface 824 by suction.The substrate support 802 forms a gas cushion that supports thesubstrate 826 between a dispenser 828 and the substrate support 802. Thesubstrate support 802 has a top surface 832 which is flat. The substrate826 is also flat and has a uniform separation distance between thedispenser 828 and a top surface of the substrate 826 in a first region833. In a second region 831, the substrate 826 is deflected to accessthe contact surface 824. The top surface of the substrate 826 thus has anon-uniform separation distance from the dispenser 828. The holderassemblies described herein have the capability to move in the thirddirection to correct such non-uniform separation. Thus, if theseparation distance of the substrate 826 from the dispenser 828 isnon-uniform due to deflection of the substrate to the contact surface824, the holder assembly 822 can be adjusted in the third direction toremove the deflection.

FIG. 8B is another activity diagram illustrating substrate edgepositioning according to another embodiment. In this case, a substratesupport 850 is used that has a tapered edge 852. The tapered edge 852 ofthe substrate support 850 is adjacent to the holder assembly 822. Thesupport surface 854 of the substrate support 850 recedes away from thesubstrate at the tapered edge 852 in a direction toward the holderassembly 822. In other words, a distance from the tapered edge 852 tothe substrate 826 declines with distance from the holder assembly 822.The tapered edge 852 minimizes edge effects in substrate processing,facilitating adjustment of the edge region in the third direction toremove non-uniformity in spacing between the substrate 826 and thedispenser 828 without risking contact between the substrate 826 and thesupport surface 854.

The tapered edge 852 is generally linear. That is, the tapered edge 852is a flat surface that forms an angle with the support surface 854between about 1° and about 20°, for example about 5°. A width 851 of thetapered edge 852 in a direction parallel to the support surface 854 isfrom about 10 mm to about 30 mm, but can be larger. Here, the taperededge 852 is shown forming a corner with the support surface 852. Thecorner may be sharp, as schematically portrayed here, or rounded orchamfered. For example, a slight chamfer of radius about 0.1 mm may beapplied to the junction between the tapered edge 852 and the supportsurface 854.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the present disclosure may be devisedwithout departing from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A substrate holder assembly, comprising: a base plate coupled to a support block; a contact member coupled to the base plate, the contact member comprising: a fulcrum; a manipulator; and a brace coupled to the fulcrum and the manipulator; a linear extender coupled between the base plate and the contact member and oriented to extend in a direction toward the contact member; and a flex member pair coupled to the base plate and the contact member, the flex member pair comprising a first flex member and a second flex member, each of the first and second flex members having a flex direction aligned with the direction.
 2. The substrate holder assembly of claim 1, wherein the first flex member is fixed to a first side of the support block and the second flex member is fixed to a second side of the support block opposite from the first side.
 3. The substrate holder assembly of claim 1, further comprising a bearing member between the linear extender and the contact member.
 4. The substrate holder assembly of claim 2, further comprising a bearing member between the linear extender and the contact member, wherein the first flex member extends between the bearing member and the contact member on a first side of the bearing member and the second flex member extends on a second side of the bearing member opposite from the first side.
 5. The substrate holder of claim 3, wherein the linear extender applies a positioning force to the contact member through the bearing member, and wherein the positioning force rotates the contact member.
 6. The substrate holder of claim 5, wherein the first flex member extends between the bearing member and the contact member on a first side of the bearing member and the second flex member extends on a second side of the bearing member opposite from the first side.
 7. The substrate holder of claim 6, further comprising a landing member disposed between the base plate and the contact member.
 8. The substrate holder of claim 7, wherein the landing member is a first landing member, and further comprising a second landing member disposed between the bearing member and the contact member.
 9. The substrate holder of claim 1, wherein the linear extender is a first linear extender, and further comprising a second linear extender coupled between the base plate and the contact member and oriented in the direction.
 10. A substrate holder assembly, comprising: a base plate; a contact member coupled to the base plate, the contact member comprising a manipulator with a vacuum surface, a fulcrum, and a plurality of braces coupling the fulcrum to the manipulator, wherein the manipulator and the fulcrum are substantially parallel members; a first linear actuator coupled to the base plate and to the contact member to move the manipulator in a first direction and rotate the contact member about an axis that extends in a second direction perpendicular to the first direction, wherein the manipulator and the fulcrum each extend in the second direction; a second linear actuator to move the contact member in a third direction substantially perpendicular to the first and second directions; and a flex member pair coupled to the base plate and the contact member, the flex member pair comprising a first flex member and a second flex member, each of the first and second flex members having a flex direction aligned with the first direction.
 11. The substrate holder assembly of claim 10, wherein the contact member is coupled to the base plate by a pivot.
 12. The substrate holder assembly of claim 11, further comprising a third linear actuator to move the contact member in the third direction, and wherein the pivot is disposed between the second and third linear actuators.
 13. The substrate holder assembly of claim 11, further comprising a plurality of landing members disposed between the base plate and the contact member.
 14. The substrate holder assembly of claim 11, further comprising a bearing member disposed between the first linear actuator and the contact member.
 15. The substrate holder assembly of claim 14, further comprising a plurality of landing members disposed between the bearing member and the contact member.
 16. The substrate holder assembly of claim 11, wherein the pivot enables the contact member to rotate about an axis parallel to the first direction. second and third actuators are members of the substrate contact member.
 17. An inkjet printer, comprising: a substrate support; a dispensing assembly coupled to the substrate support; and a substrate holder assembly coupled to the substrate support, the substrate holder assembly comprising: a base plate; a contact member coupled to the base plate by a pivot, the contact member comprising a manipulator with a vacuum surface, a fulcrum, and a plurality of braces coupling the fulcrum to the manipulator, wherein the manipulator and the fulcrum are substantially parallel members; a first linear actuator coupled to the base plate and to the contact member to move the manipulator in a first direction and rotate the contact member about an axis that extends in a second direction perpendicular to the first direction, wherein the manipulator and the fulcrum each extend in the second direction; a second linear actuator to move the contact member in a third direction substantially perpendicular to the first and second directions; and a flex member pair coupled to the base plate and the contact member, the flex member pair comprising a first flex member and a second flex member, each of the first and second flex members having a flex direction aligned with the first direction.
 18. The inkjet printer of claim 17, wherein the substrate holder assembly further comprises a third linear actuator to move the contact member in the third direction, and wherein the pivot is disposed between the second and third linear actuators.
 19. The inkjet printer of claim 18, wherein the second and third linear actuators are operable to rotate the contact member about the pivot.
 20. The inkjet printer of claim 17, further comprising a bearing member between the first linear actuator and the contact member, wherein the first and second flex members extend on opposite sides of the bearing member. 